1. Industrial Field
The present invention relates to a heat resistant roll for use in steel plate manufacturing equipment and, more particularly, to a heat resistant roll applicable to continuous annealing apparatus, exit side of baking furnace of continuous coating apparatus or exit side of galvanizing tank of continuous zinc galvanizing apparatus.
2. Prior Arts
Hitherto, heat resistant rolls have been used as rolls for conveying and grasping steel plate heated to a high temperature, in continuous annealing apparatus and the like. These conventional heat resistant rolls have been provided in the form of metalized roll of chromium oxide or tungsten carbide, rubber roll of heat resistant rubber, fiber roll of heat resistant fiber such as heat resistant polyester fiber or the like.
A serious problem, however, exists in that when employing any of the conventional heat resistant rolls, the heat resistant roll may pick up metal powder existing on the surface of steel plate resulting in sticking of such metal powder to the surface of the heat resistant roll. Further, when baking a coating material after applying the coating material to the surface of a steel plate and conveying the steel plate after the baking, there arises a problem that heat resistant roll may pick up unbaked coating material which may stick to the surface of the heat resistant roll. Furthermore, when applying a zinc galvanization to a surface of steel plate and conveying the steel plate after the zinc galvanization, there arises a problem that heat resistant roll may pick up the galvanizing zinc which may stick to the surface of the heat resistant roll. Moreover, scratch may occur on the surface of conveyed plate, coating layer or galvanization layer due to the sticking metal powder, coating material or zinc, eventually resulting in reduction in the yield of steel plate.
To overcome the mentioned disadvantages pertinent to the prior arts, the inventors have been engaged in various researches for the reason why the conventional heat resistant rolls may pick up metal powder, etc. As a result of the researches, it was acknowledged by the inventors that any of the conventional rolls had affinity with metal powder, coating material, etc. under high temperature. More specifically, it was recognized by the inventors that surface of the conventional metalized roll, etc. and metal powder, etc. are very affinitive with each other and, accordingly, metal powder, etc. is easy to stick to the surface of the roll, which results in undesirable phenomenon of picking up metal powder, etc.